Going South

   One of the most apparent astronomical phenomena is the change in the number of daylight hours as the seasons progress. Even observers in the most frustrating light polluted skies notice the earlier and earlier sunsets this time of year. On the twenty third of this month, the Sun will cross the celestial equator as it seems to move around the ecliptic. This is the date of the Autumnal Equinox. For residents of the northern hemisphere, the number of daylight hours is decreasing at the greatest rate at this time of year.
   Consider this. For observers at mid northern latitudes, such as myself, the time of sunset at the end of September is ninety minutes earlier than on the first day of the month!. Oh, you do know that the Earth is getting closer to the Sun every day in the month of September. But as you also should know, the tilt of Earth's rotation axis is more important in determining our seasons than the shape of our orbit.

   The Full Moon occurs on the twenty-sixth day of the month. The Full Moon of September is known as the Fruit Moon according to Guy Ottewell and the Astronomical Calendar. This year's September Full Moon also be the Harvest Moon.

   In September, look for the Summer Triangle nearly overhead in mid-northern latitudes, right after sunset. If your skies are obscured by lights, these may be the only three stars you can see. That is a pity. The summer Milky Way is a sight to behold. For you campers out there, try to get out in dark skies one more time before autumn closes in.